Mining machine having synchronized oscillating cutter heads



TTER HEADS Aug. 1, 1967 R. c. ANDERSON MINING MACHINE HAVING smcnnomzmn oscmumuc cu 5 Sheets-Sheet 1 Filed Sept. 25,. 1964 mm 0? 0N mm mm mm on INVENTOR. ROGER C. ANDERSON is A TOBN E Y 1967 R. c. ANDERSON 3,333,895

MINING MACHINE HAVING SYNCHRONIZED OSCILLATING CUTTER HEADS Filed Sept. 25,. 1964 5 Sheets-Sheet 2 4o Fig.3.

1* I68 M64 54 INVENTOR. I62 I50 ROGER C.ANDERSON L BY '60 :52 (AM u I48 W his ATTORNEY Aug. 1. 1967 R. c. ANDERSON 3,333,895

MINING MACHINE HAVING SYNCHRONIZED OSCILLATING CUTTER HEADS Filed Sept. 25, 1964 5 Sheets-Sheet if I25 I32 I22 Fig-6. I30/ 74 r Fig.

3 8 74 I27 I38 I30 Ff? A as Pf Q L I I F A *3. 42 INVENTOR.

42 ROGER 0. AND R 2 4- 82 BY E SON 8 74a76 72a 76a 74 72 5M F 98.

his ATTORNEY Aug. 1, 1967 R. c. ANDERSON MINING MACHINE HAVING SYNCHRONIZED OSCILLATING CUTTER HEADS 5 Sheets-Sheet Filed Sept. 25, 1964 N mo 4 6 T5 4 4 NR 2 EE VD NN A a c i M R r i 2 43 E ;r1l.| 22a 6 22 O R his ATTORNEY Aug. 1, 1967 R. c. ANDERSON 3,333,895

MINING MACHINE HAVING SYNCHR ONIZED OSCILLATING CUTTER HEADS Filed Sept. 25, 1964 5 Sheets-Sheet E I I I l I 352 F :g I3.

CYL. FULLY EXTENDED PRESSURE CYL. RETRACTING PRESSURE 302 F lg. I4. CYL. FULLY RETRACTED CYL. EXTENDING PRESSURE INVENTOR. ROGER C.ANDERSON RETURN BY 6 W w. F I 9.12

his ATTORNEY United States Patent MINING MACHINE HAVING SYNCHRONIZED OSCILLATING CUTTER HEADS Roger C. Anderson, Franklin, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 25, 1964, Ser. No. 399,178

Claims. (Cl. 299-1) This invention relates to a continuous mining apparatus having a pair of mineral disintegrating or cutter heads and more particularly to a new and improved means for oscillating the cutter heads in opposite directions and in phase.

In a continuous mining apparatus of a known type, a pair of disintegrating heads are sometimes employed in dislodging mineral from the mine vein and are operable to provide a mine passageway or room into which the apparatus advances as mining progresses. The disintegrating head mechanisms are usually pivotally mounted on a mobile base to swing in a vertical plane between the mine roof and floor and may include rotary cutters arranged on horizontal transverse axes having teeth or bits which tear away and disintegrate the mineral. The apparatus also includes a conventional loading head for gathering the loose mineral on the mine floor and moving it inwardly toward the forward receiving portion of the conveying means of the apparatus. Such apparatus further includes a mechanical means for traversing or oscillating the cutter heads back and forth in a horizontal direction while rotating the cutters so that the total transverse distance over which the cutters operate is wider than the transverse distance of the apparatus to provide adequate clearance on each side of the apparatus.

The prior known devices employed common driving means for rotating the cutter discs and for oscillating the cutter heads by various gearing arrangements so that rotation of the cutters effected oscillation of the cutter heads. Accordingly, oscillation could not be interrupted at any intermediate position without terminating the operation of the rotary cutters, thereby restricting the overall efiiciency of the machine. In the case of worm and crank arrangements, oscillation, velocity and acceleration were continuously variable. Furthermore, these devices required a multitude of moving parts which were subject to severe vibration, wear and excessive loads. Also, any adjustment with respect to the speed or rate of oscillation required a change in the ratio of the worm gears which necessitated the breakdown and replacement of parts.

The present invention as hereinafter described contemplates an improvement over such known type of mining apparatus and obviates the disadvantages set out above by employing a hydraulic or pressure fluid means for oscillating a pair of cutter heads which means is compact, simple in construction, requires only a minimum number of parts is reliable in operation.

Another advantage residing in the apparatus of this invention is that oscillation of the cutter heads is independent of the cutter drive means so that the cutter heads can be interrupted in various transverse positions without terminating the cutting operation, thereby facilitating rib slabbing turning cross cuts, and cutting large lumps of mineral resulting from roof falls.

A further advantage residing in the apparatus of this invention is that frequency of oscillation may be readily varied by changing the volume of oil delivered to the circuit without the need for replacing various parts in areas of limited accessibility.

It is therefore an object of thi invention to provide a new and improved continuous mining apparatus.

It is another object of the present invention to provide a new and improved continuous mining apparatus having novel cutter head oscillating means.

It is a further object of this invention to provide a new and improved continuous mining apparatus having hydraulic means for oscillating a pair of cutter heads at a uniform rate in a horizontal transverse direction.

It is a specific object of the present invention to provide a new and improved continuous mining apparatus having hydraulic means, independent of the cutter drive mechanism, for oscillating a pair of cutter heads so that oscillation of the cutter heads may be interrupted in any selected transverse position without terminating the cutting operation.

It is a more specific object of this invention to provide a new and improved continuous mining apparatus having hydraulic actuators for oscillating a pair of cutter heads in opposite directions and in step, said actuators having pistons with spool valves contained therein for controlling the movement and direction of the cutter heads.

It is another more specific object of this invention to provide a new and improved continuous mining apparatus having hydraulic means including a shifter valve mechanism for controlling the oscillation of a pair of cutter heads in opposite directions and in phase.

It is still another more specific object of this invention to provide a new and improved continuous mining apparatus having hydraulic means including an intermittently rotatable selector valve for controlling the oscillation of a pair of cutter heads in opposite directions and in phase.

These and other objects of this invention will become more apparent when taken in conjunction with the following detailed description and drawings, in which:

FIG. 1 is a top plan view of the mining apparatus constructed in accordance with the principles of this invention;

FIG. 2 is a side elevational view of the mining apparatus as shown in FIG. 1;

FIG. 3 is an enlarged elevational view of one of the oscillating arms with the side plate removed and a portion of the arm broken away;

FIG. 4 is an enlarged longitudinal sectional view of a hydraulic cylinder constructed in accordance with the principles of this invention;

FIG. 5 is a diagrammatic view illustrating the hydraulic circuit for the independent oscillating drive means;

FIG. 6 is an enlarged sectional view showing the pilot valve in one of its positions;

FIG. 7 is an enlarged sectional view showing the pilot valve in an alternate position;

FIG. 8 is an enlarged, partial, fragmentary top plan view of the apparatus of this invention with a portion of the cover plate broken away to show the mounting of the actuating cylinders with respect to the oscillating arms;

FIG. 9 is an enlarged, diagrammatic, plan view, with parts omitted, of another embodiment of the mining apparatus of this invention;

FIG. 10 is an enlarged central, longitudinal sectional view through one-half the pilot shifter valve mechanism of the embodiment shown in FIG. 9;

FIG. 11 is a diagrammatic view illustrating the hydraulic circuit for the embodiment of FIG. 9;

FIG. 12 is a diagrammatic view showing the Geneva stop mechanism of a third embodiment of the mining apparatus of this invention;

FIG. 13 is a view similar to FIG. 12 showing a second position of the Geneva stop mechanism;

FIG. 14 is a diagrammatic view showing the hydraulic circuit for the third embodiment;

FIG. 15 is a diagrammatic view illustrating the porting arrangement of the selector valve of the embodiment 3 shown in FIG. 14 with the actuating cylinder in the fully extended position;

FIG. 16 is a view similar to FIG. 15 showing the porting arrangement of the selector valve when the cylinder is retracting;

FIG. 17 is a view similar to FIG. 15 showing the porting arrangement of the selector valve with the cylinder in the fully retracted position; and

FIG. 18 is a view similar to FIG. 15 showing the porting arrangement of the selector valve when the cylinder is extending.

Referring to the drawings and particularly to FIGS. 1 and 2, it will be observed that a continuous mining apparatus constructed in accordance with the principles of this invention comprises a mobile base having a frame 12 mounted on suitable self propelling and steering means 14. Arranged rearwardly of the frame at one side thereof is an operators control station indicated generally at 15 which is provided with a suitable control valve mechanism and other control appurtenances which need not be detailed here.

Carried by frame 12 at the forward end thereof is a suitable tiltable loading head 16 embodying conventional oscillatory gathering foldable arms 18 for gathering loose material on the mine floor and for moving the material so gathered onto the forward receiving portion of an endless flight conveyor generally indicated as 20. Conveyor 20 extends substantially along the length af the apparatus and terminates at a discharge section generally designated 22, which discharge section is swingable about a vertical axis and tiltable about a horizontal axis, respectively, as is well known in the art. The gathering head is tiltable about a horizontal axis by means of a pair of fiuid jacks 24 (only one of which is shown in FIG. 2). Since the structure of the gathering mechanism and the conveyor mechanism is conventional and has been widely used in well known commercial structures by applicants assignee, it is believed that no further illustration is required.

An elongated boom frame generally designated as 26 is pivotally mounted at its lower rear end on a horizontal axis 28 located on the main frame 12. For purposes of this description, the forward end of the apparatus will be taken as the right hand side of the apparatus as seen in FIG- URES l and 2. Frame 26 is of substantial width as shown in FIGURE 1 and projects forwardly over and beyond the tiltable loading head 16 in the manner shown in FIGURE 2.

The boom frame may be swung in vertical planes about its pivot by means of suitable extensible hydraulic jacks 30 comprising cylinders 32 suitably pivotally mounted at '34 on main frame 12 and these cylinders contain suitable reciprocable pistons having forwardly extending piston rods 36 suitably pivotally mounted at 38 to the rear portion of boom frame 26. Thus when liquid under pressure is properly supplied to the hydraulic jacks 30, the boom frame may be swung either upwardly or downwardly about its pivot to vary the elevation thereof and by trapping liquid within the cylinders at the opposite sides of the piston, the boom frame may be locked in any selected position.

Pivotally supported by universal connections herein preferably in the form of ball and socket pivotal mountings 40 (FIGS. 1 and 3) and projecting forwardly therefrom are a pair of elongated oscillating arms generally indicated as 42. Each arm comprises an elongated hollow tubular member 44 having a cutter head or gear case housing 46 disposed at the forward end thereof for enclosing a suitable drive mechanism (not shown) for ro ta-ting a suitable transverse shaft 48. A series of spaced rotary cutter discs 50 are rigidly secured to each shaft 48 and are rotatable therewith. Although preferably each cutter head has three rotary discs as illustrated, it will be obvious that, if desired, more or less than three discs may be utilized. As is well known in the art, a plurality of cutter bits (not shown) are rigidly secured to the cutter discs, respectively, adjacent the peripheries thereof in and desired pattern.

In order to effect rotation of rotary discs 50, a pair of suitable motors 52 are mounted at the sides of boom frame 26 and are operatively connected through suitable associated gearing (-not shown) to a suitable shaft 54 located in tubular member 44 as shown in FIGURE 3, which shaft is operatively connected to the drive mechanism (not shown) enclosed in housing 46. Such gearing arrangements for driving the shaft 48 and thereby discs 50 may be of any conventional variety, and since many such arrangements are known in the art, no further illustration is believed necessary.

For the purpose of protecting the oscillation controls, hereinafter more fully described, and the cutter head gear cases, a massive shrouding generally designated as 56 is provided. Such shrouding comprises a top cover plate 58, a bottom cover plate 60 and side cover plates 62 (only one of which is shown in FIGURE 2). Bottom plate 60 supports the forward ends of the oscillating arms and also the actuating cylinders, hereinafter more fully described. A front plate 68 is rigidly secured, as by means of welding for example, between the top and bottom cover plates 58 and 60 respectively (FIG. 8). A pair of movable plates 70 extend laterally inwardly from housings 46 respectively, and cooperate with front plate 68 to form a front face of the shrouding so that the oscillation controls and cutter head gear cases may be protected in any lateral position of oscillating arms 42.

For the purpose of providing a continuous uniform oscillating motion to the oscillating arms, hydraulic means are provided, such means comprising a pair of hydraulic cylinders generally designated 72 and 72a (FIG. 8), each cylinder being connected between the boom frame 26 and an oscillating arm 42.

Hydraulic cylinders 72 and 72a are arranged at the forward central portion of the shrouding 56 (FIG. 8) and comprise elongated shOllOW cylindrical bodies or casings 74, 74a, pivotally mounted at their head ends at 76, 76a respectively, to brackets 78, 78a secured to front plate 68. These cylinders contain pistons 86 (not shown in FIG. 8 but hereinafter more fully described) having laterally and outwardly extending piston rods 80, 80a pivotally connected at 82, 82a respectively, to brackets 84, 84a secured to the inner sides of housings 46 of oscillating arms 42.

Cylinders 72 and 72a are similar in construction with the exception of cylinder 72 having a conventional hydraulic motor 88 associated therewith as shown in the diagrammatic view of FIG. 5. Motor 88 drives an output shaft 90 (FIG. 4) having a small pinion gear 92 rigidly secured thereto. Output shaft 90 is adapted to receive a shaft (indicated diagrammatically as 91 in FIG. 5) for synchronously driving a small pinion gear 92a associated with cylinder 72a, said gear being identical to gear 92. Since cylinders 72 and 72a are similar in construction, the description will be restricted to cylinder 72 as shown in FIGS. 4, 6 and 7.

rPinion gear 92 meshes with a larger gear 94 mounted on an elongated actuating shaft 96 which is suitably journalled within bearing 98, such bearing being supported in the head 100 of casing 74. A lock nut 102 is provided for holding the shaft 96 within bearing 98 and for retaining gear 94 on such shaft. Bearing 98 is held in posit-ion in head 100 by means of a snap ring 103. A right and left hand diamond thread 104 is provided over that portion of shaft 96 which extends into the cylinder casing.

An actuating spool valve 106 is slidably contained within a bore 108 of piston 86 for limited linear movement relative thereto and is retained in the piston by means of a locking nut 110. Actuating valve 106 has a central bore 112 for receiving shaft 96 and is provided with a pivotable tooth or projection 114 that is biased radially inwardly by a spring 115 into such bore for engaging the thread of the shaft. Consequently, when the shaft is rotated, the valve travels back and forth in a linear direction over the threaded area of the shaft toward either end of casing 74.

Bore 108 of piston 86 is provided adjacent the central portion thereof with three annular enlargements or grooves 116, 118 and 120, respectively. Grooves 116 and 120 are connected to an elongated exhaust passageway 122 by passages 124 and 126, respectively. Exhaust passageway 122 is connected to exhaust port 125 which is connected to a return conduit leadingto tank. A passage 127 connects groove 118 to an elongated pressure passageway 128 which in turn is connected to a pressure port 130, which communicates with the pressure line.

Actuating spool valve 106 is provided adjacent the central portion thereof with two annular recesses 132 and 134, respectively, which direct fluid flow through the piston and are alternately connected to pressure and exhaust. Passageway 136 connects recess 132 to the left side or head end of piston 86 as seen in FIGURES 4, 6 and 7 and passageway 138 connects recess 134 to the right side or rod end thereof.

Referring now to the diagrammatic showing of the hydraulic circuit in FIGURE 5, it will be observed that a source of hydraulic fluid is shown at 140 as, for example, a suitably disposed tank or receptacle to contain the necessary quantity of hydraulic fluid. The source 140 is connected by a suitable suction line 142 with a suitable pump 144 which is driven from any suitable source of power, not shown.

Pump 144 delivers fluid under pressure to a line 146 which is connected with the main hydraulic control valve 148. Leading from the control valve 148 is a conduit 150 connected to a suitable pressure reducing valve 152 which in turn is connected by means of a conduit 154 to hydraulic motor 88. Motor 88 is connected to a conduit 156 which leads back to the source 140 by means of return conduit 158.

Also leading from the control valve 148 is a conduit 160 connected to a conventional flow divider 162, which is connected by means of conduits 164 and 166 to suitable relief valves 168 and 170 respectively. Conduits 172 and 174 connect relief valves 168 and 170 respectively, to the pressure ports of actuating cylinders 72 and 72a respec tively. Exhaust ports 125 of actuating cylinders 72 and 72a are connected with suitable conduits 176 and 178, respectively, which lead back to the source 140 by way of return conduit 158. The general mode of operation of the improved mining apparatus above described is as follows: When the working face is reached with the cutter discs located at the face of the mine vein, the cutter discs may be raised or lowered into various selected fixed vertical positions or continuously raised and lowered by swinging boom frame 26 about horizontal axis 28 by means of hydraulic jacks f Motors 52 may then be operated to rotate the two shafts 48 andcutter discs 50 secured thereto, and the conveying mechanism and gathering mechanism may be operated concurrently in the conventional manner, and the apparatus may be advanced by the tractor base bodily over the mine floor to feed the cutters toward the work to penetrate the latter thereby to effect the mining operation.

During the cutting operation cutter heads 46 may be oscillated in a horizontal or lateral direction with their direction of motion always opposite and'in step in the following manner: Hydraulic fluid under suitably reduced pressure is applied to hydraulic motor 88 causing it to rotate actuating shafts 96 of cylinders 72 and 72a, respectively, while hydraulic fluid under suitable pressure is simultaneously applied to pressure ports 130 of hydraulic cylinders 72 and 72a. Assume that cutter heads 46 have completed one-half the cycle of oscillation whereat they are located in the laterally outwardly extended position and are about to be moved laterally inwardly. Rotation of shaft 96 effects linear movement of pilot valve 106 to the left with respect to piston 86 as illustrated in FIG- URES 4 and 6. Pressure fluid flow is established through port 130 and passageway 128 between passages 127 and 138 by means of groove 118 and recess 134 and is directed to the rod or right hand end of piston 86 and will cause movement of the piston to the left carrying along with it oscillating arm 42. Fluid existing on the left side of piston 86 will be exhausted by way of passage 136, recess 132, groove 116, passage 124, passageway 122 and exhaust port to tank thus allowing movement of piston 86 to the left.

Slight movement of the piston 86 leftwardly tends to center the piston relative to the spool valve and establish a neutral position by uncovering both recesses 132, 134 so that pressure fluid in groove 118 could be directed to passageways 136 and 138 via recesses 132, 134 which would equalize the pressure on both sides of piston 86. However, because spool valve 106 is continuously moving to the left, piston 86 does not move a sufficient distance relative to the spool valve 106 to effect such a neutral position until the spool valve 106 reaches the end of its travel at the left end of the thread 104.

It will be evident that on the opposite movement of pilot valve 106 by means of continually rotating shaft 96, alternate connections between pressure and exhaust will be effected so as to move oscillating arm 42 outwardly or to the right as viewed in FIGURES 1 and 5. Specifically, as shown in FIGURE 7, pressure fluid flow is established between passages 127 and 136 by means of uncovered recess 132 and is directed to the left hand side of piston 86 while fluid on the right side of piston 86 will be exhausted by way of passage 138, recess 134, groove 120, passage 126, passageway 122 and exhaust port 125 to tank.

Valve 106 has a relatively small linear motion within the piston, as for example, on the order of of an inch, permitting the edges of the recesses to seat against mating edges of the inside of the piston, thus directing flow to either end of the piston. The passages 136 and 138 of the piston serve two ways, either pressure or exhaust, depending on the position of the valve inside the piston. The valve and piston arrangement effect a sort of reflex action comparable to that of the human body in that the valve is the brain issuing orders and the piston is the muscle that does the work. Wherever the valve is located on the actuating shaft, the piston wants to follow. The piston always wants to center itself over the valve providing fast, accurate, linear travel. Of course, movement of piston 86 carries oscillating arm 42 in the same direction by means of piston rod 80. Oscillating arms 42, carrying cutter heads 46, are oscillated in opposite horizontal directions in step by properly coupling flexible shaft 91 to cylinders 72 and 72a. The frequency of oscillation may be readily varied by changing the volume of fluid delivered to the circuit. As hereinbefore stated, oscillation can be stopped at any horizontal position within its cycle without terminating or affecting the cutting operation.

From the foregoing it is apparent that an improved mining apparatus is obtained by employing an independent pressure fluid means for oscillating a pair of cutter heads. Such means permits the use of a low pressure hydraulic circuit and requires only one pressure line per cylinder, resulting in lower initial costs and maintenance. Also, placing the spool valve within the cylinder piston eliminates hoses, line surges and lag or hesitation in oscillation.

I FIGURES 9, 10 and 11 illustrate another embodiment of the continuous mining apparatus of this invention which is very similar to the general arrangement of the above described embodiment with the exception of the hydraulic circuitry and the mechanism for oscillating arms 42. With reference to FIGURE 9, an elongated flat bracket 200 is rigidly attached, as by means of welding, for example, to the right oscillating arm 42' as shown in FIGURE 9. Extending vertically upwardly from bracket 200 are a pair of abutment pins 202 and 204, which are adapted to engage extensions 206 and 208 respectively, of a pilot shifter valve mechanism designated generally as 210, said shifter valve being rigidly mounted on a bracket 212 which is rigidly secured to the other oscillating arm 42'.

With reference to the diagrammatic view of FIGURE 11, it will be observed that a source of hydraulic fluid is shown at 214, as for example, a suitably disposed tank or receptacle to contain the necessary quantity of hydraulic fluid. Source 214 is connected by a suitable suction line 216 with a pump 218, which is driven from any suitable source of power, not shown. Pump 218 delivers fluid under pressure by means of conduit 217 to the operators control valve 220. Leading from the control valve is a suitable pressure line 222 which is connected to a conventional flow divider 223, which in turn is mounted by suitable pressure conduits 224 and 225 to suitable relief valves 226 and 227, respectively. Leading from the relief valves are conduits 228 and 229 which are connected to the pilot shifter valve mechanism 210. This valve mechanism is connected by conduits 230, 231, 232 and 233 to return line 234 which leads back to the source 214. Conduits 235 and 236 connect the shifter valve 210 to the head ends of cylinders 237 and 238, respectively, while conduits 239 and 240 connect the shifter valve to the rod ends of said cylinders.

Cylinders 237 and 238 are of the conventional double acting type and are mounted between the boom frame and the oscillating arms in the same manner as cylinders 72, 72a of the embodiment first described with the exception that the head and rod ends are reversed. It is contemplated, however, that the mounting of cylinders 237 and 238 may be similar to that of the first embodiment, if desired.

Because the left hand portion of shifter valve 210 is identical to the right hand portion, the description will be restricted to the left hand portion only. The valve mechanism 210 includes a chest 242 having a bore 244 in Which an elongated pilot valve element 246 is reciprocable. Element 246 has oppositely projecting extensions 206 and 208 (not shown in FIG. 10) which are adapted to be engaged by abutment pins 202 and 204 as oscillating arms 42' move in opposite directions.

Bore 244 is provided between its ends with seven annular grooves or enlargements numbered 256, 258, 260, 262, 264, 266 and 268 respectively. Grooves 256 and 260 are connected together by a passage 270 and groove 256 is connected with port 272 communicating with conduit 230. Grooves 264 and 268 are connected together by a passage arrangement 274 and groove 268 is connected with port 276 communicating with conduit 232. Grooves 258 and 266 are connected to exhaust lines 224 and 226 respectively, by ports 278 and 280 respectively. Groove 262 is connected to port 282 which in turn is connected to conduit 222 which serves to supply fluid under pressure to the shifter valve mechanism.

The mode of operation of this embodiment will be readily understood. Assume that arms 42' have moved laterally inwardly so that pin 204 engages stem 208 to shift element 246 to the left, a condition which is shown in FIGURE 10. Pressure fluid flow is then established through port 282, groove, 262, groove 264, passage 274, groove 268, port 276, line 232 and is directed to the head end of cylinder 238. Pressure fluid in bore 244 acts on the pilot valve element similar to a cylinder piston and forces the pilot valve element quickly in the leftward direction and holds it there. Of course, pressure fluid flow will be directed to the head end of cylinder 237 in the same manner.

Exhaust will be established through conduit 240, con duit 230, port 272, groove 256, passage 270, groove 260, groove 258-, port 278, conduits 233 and 234 back to the source 214. Since the piston rods of cylinders 237, 238 are secured to the boom frame, the cylinder casings will move outwardly, causing arms 42 to move outwardly in opposite directions. Upon reaching their laterally outwardly extended position, abutment pin 202 will engage extension 206 to shift valve element to the right, thus reversing pressure and exhaust flow to cause arms 42' to move inwardly in opposite directions.

This embodiment has an advantage over the first embodiment described in providing the quick shift feature in order to minimize throttling and allow a quick reversal of movement of the arms.

It is to be realized that other means may be employed to effect such a quick shift for controlling alternate connections between pressure and exhaust to the cylinders. By way of example, a lost motion mechanical linkage adapted to be operated by the moving arms can be utilized to quickly shift a valve spool of a conventional hydraulic control valve and to hold such spool in the shifted position for a given portion of a cycle.

FIGURES 12, 13, 14, 15, 16, 17 and 18 illustrate still another embodiment of the continuous mining apparatus of this invention which is very similar to the general arrangement of the embodiment first described with the exception of the hydraulic circuitry for oscillating arms 42.

Referring now to the diagrammatic showing of the hydraulic circuit in FIGURE 14, a source of hydraulic fluid is shown at 300, as for example, a suitably disposed tank or receptacle to contain the necessary quantity of hydraulic fluid. Source 300 is connected by suitable suction line 302 with a suitable pump 304 which is driven from any suitable source of power, not shown.

Pump 304 delivers fluid under pressure to a line 306 which is connected with the hydraulic control valve 308. Leading from the control valve 308 is a conduit 310 connected to a suitable pressure reducing valve 312 which in turn is connected by conduit 314 to a hydraulic motor 316. Motor 316 is connected to a conduit 318 which leads back to the source 300.

Also leading from control valve 308 are conduits 320 and 322 which are connected to a rotary selector valve 324 and direct fluid under pressure thereto. Conduits 326 and 328 connect rotary selector valve 324 to the source 300.

A pair of conventional double acting hydraulic actuating cylinders 330 and 332 are mounted between the boom frame and oscillating arm in the same manner as cylinders 238 and 240 of the second embodiment described. Conduits 334 and 336 connect selector valve 324 to the head end and the rod end respectively of cylinder 330. Conduits 338 and 340 connect selector valve 324 to the head end and rod end respectively of cylinder 332.

Motor 316 drives a Geneva stop type mechanism 342 which comprises a circular disc 344 (FIG. 12) having an extension 346 extending from the periphery thereof, such extension having an elongated cylindrical pin 348 rigidly secured thereto. Disc 344 is continuously rotated by a power shaft which is driven by motor 316. A rotatable star wheel 350 has four slots 352, which are spaced apart and are adapted to be engaged by pin 348 for the purpose of intermittently rotating said star wheel which in turn rotates the selector valve 324 by means of a shaft for controlling pressure and exhaust flow to and from the cylinders 330, 332. It is to be understood that the Geneva stop mechanism may be mounted in any convenient or desirable location on either frame 12 or boom frame 26.

FIGURES 15, 16, 17 and 18 show the diagrammatic porting of one-half the selector valve 324 for cylinder 332. It is to be understood that the other half of selector valve 324 has an identical porting arrangement for cylinder 330.

The mode of operation is as follows: Assume that cylinders 330 and 332 are fully extended so that the oscillating arms are in the laterally outwardly extended position and the diagrammatic porting of selector valve 324 for cylinder 332 is as shown in FIGURE 15. Members 344 and 350 will be in the position shown in FIGURE 12. Member 344 is uniformly rotated through /8 of a revolution by motor 316. Wheel 350 is rotated with a variable angular velocity through /3 of a revolution by means of pin 348 and slot 352. Such rotation establishes a connection between fluid pressure and the rod end of cylinder 332 (FIGURE 16) while permitting exhaust of fluid from the head end of cylinder 332 to return. Wheel 350 is stationary while disc 334 rotates of a revolution and cylinder 332 retracts at a uniform rate carrying along with it the oscillating arms. Pin 348 then engages slot 352 to turn wheel 350 /s of a turn to close the pressure and exhaust ports (FIG. 17) bringing the cylinder to rest. The following A; of a turn of wheel 350 indexes the selector valve 324 to the position shown in FIGURE 18, which reverses the fluid pressure flo-w to the head end of cylinder 332 so as to extend the cylinder which carries the oscillating arm-With it. It is to be noted that the cylinders are extended and retracted during of a revolution of star wheel 350. The cycle is repeated to effect horizontal oscillating movement of the cutter heads in opposite directions and in phase.

This embodiment has the advantage of utilizing only one cylinder circuit, if desired, thereby permitting selective use of the cutter units. Also, abrupt changes in direction are eliminated by the acceleration and deceleration characteristics obtained by valve throttling when the end of the stroke is reached.

Preferred embodiments of the principles of this invention having been described and illustrated herein, it is to be realized that modifications thereof can be made without departing from the broad spirit and scope of this in vention as defined in the appended claims.

I claim:

1. In a mining apparatus having: a mobile frame; a pair of forwardly extending elongated support arms mounted at one end thereof on said mobile frame for pivotal movement about spaced axes respectively; cutting means carried at the other end of each of said support arms the improvement comprising fluid operated drive means for said support arms for oscillating said support arms through a given cycle about said axes in opposite directions, respectively; said drive means having a pair of valves therein each having a member positionable to direct fluid flow through said drive means to synchronize the oscillations of said support arms; and control means cooperable with said valves operative to position said members relative to said valves in response to a variation in the oscillation rate of one of said support arms to direct the fluid flow to cause a like change in the oscillation rate of the other of said arms.

2. In a mining apparatus as specified in claim 1 the improvement as therein set forth wherein: another member of each valve is mechanically connected to a respective support arm and movable thereby.

3. -In a mining apparatus having a mobile frame; a pair of forwardly extending elongated support arms mounted at one end thereof on said mobile frame for pivotal movement about spaced axes, respectively; cutter heads rotatably mounted at the other ends of each of said support arms; fluid operated drive means for each of said support arms for oscillating said support arms through a given cycle about said axes in opposite directions, respectively; the improvement comprising means for directing fluid flow to each of said drive means, individually, said directing means including a pair of servo valves and control means operative with said servo valves for positioning said servo valves for directing fluid flow through said drive means for oscillating said support arms, and said control means including means for shifting one of said servo valves in response to a decrease in the oscillation rate of one of said support arms for causing redirection of the fluid flow for oscillating the other of said arms.

4. In a mining apparatus having a mobile frame; a pair of forwardly extending elongated support arms mounted at one end thereof on said mobile frame for pivotal movement about spaced axes respectively; a cutter head rotatably mounted at the other end of each of said support arms, respectively; a double acting hydraulic cylinder connected between said mobile frame and each of said support arms for oscillating said support arms through a given cycle about said axes in opposite directions, respectively; a pair of servo valves mechanically connected to said support arms for regulating fluid flow through said cylinders, respectively, motor operated camming means rotatably mounted on said mobile frame; actuating means connected between said camming means and said servo valves to synchronize the oscillations of said support arms and to operate said servo valves in response to a decrease in the oscillation rate of one of said support arms to cause a like change in the oscillation rate of the other of said arms.

5. In a mining apparatus having a mobile frame; a boom frame mounted on said mobile frame for pivotal movement about a first axis; a pair of arms mounted on said boom frame for pivotal movement about spaced axes, respectively; cutter heads spaced from said spaced axes and supported by said arms respectively; means for actuating said cutter heads; and means for oscillating said arms about said spaced axes, respectively; the improvement in said oscillating means comprising: a fluid opera-ted means operatively connected to each of said arms for oscillating said arms about said spaced axes, respectively; including a source of pressurized fluid; cylinder means connected with said source; piston means in said cylinder means operatively connected to one of said arms; valve means in said cylinder means movable relative to said piston means for causing pressurized fluid to selectively flow to either side of said piston means, said valve means and said piston means being in a neutral position with respect to each other when said arms are not oscillating such that the pressurized fluid flows to both sides of said piston means to cause an equal force on both sides of said piston means; actuating means for moving each of said valve means relative to said piston means such that pressurized fluid is directed to one side of each of said piston means to move said arms together in opposite directions; and fluid directing means operatively connecting said fluid operated means for changing the rate of oscillation of one of said arms in response to a change in the rate of oscillation of the other of said arms; said means for changing the oscillation rate including mechanical means connecting said actuating means to each other for changing the movement of one of said valve means in response to a change in movement of the other of said valve means such that said one of said valve means is in a neutral position with respect to said piston means associated with said one of said valve means.

References Cited UNITED STATES PATENTS 486,567 11/1892 Monday 91226 1,880,091 9/1932 Hughes 299-71 X 2,370,376 2/ 1945 Snell 91-40 2,437,391 3/1948 Klein et al. 91286 3,052,454 9/1962 Sibley 299--71 3,170,732 2/1965 Hlinsky 29971 3,302,947 2/1967 Hlinsky 299-71 X ERNEST R. PURSER Primary Examiner. 

1. IN A MINING APPARATUS HAVING: A MOBILE FRAME; A PAIR OF FORWARDLY EXTENDING ELONGATED SUPPORT ARMS MOUNTED AT ONE END THEREOF ON SAID MOBILE FRAME FOR PIVOTAL MOVEMENT ABOUT SPACES AXES RESPECTIVELY; CUTTING MEANS CARRIED AT THE OTHER END OF EACH OF SAID SUPPORT ARMS THE IMPROVEMENT COMPRISING FLUID OPERATED DRIVE MEANS FOR SAID SUPPORT ARMS FOR OSCILLATING SAID SUPPORT ARMS THROUGH A GIVEN CYCLE ABOUT SAID AXES IN OPPOSITE DIRECTIONS, RESPECTIVELY; SAID DRIVE MEANS HAVING A PAIR OF VALVES THEREIN EACH HAVING A MEMBER POSITIONABLE TO DIRECT FLUID FLOW THROUGH SAID DRIVE MEANS TO SYNCHRONIZE THE OSCILLATIONS OF SAID SUPPORT ARMS; AND CONTROL MEANS COOPERABLE WITH SAID VALVES OPERATIVE TO POSITION SAID MEMBERS RELATIVE TO SAID VALVES IN RESPONSE TO A VARIATION IN THE OSCILLATION RATE OF ONE OF SAID SUPPORT ARMS TO DIRECT THE FLUID FLOW TO CAUSE A LIKE CHANGE IN THE OSCILLATION RATE OF THE OTHER OF SAID ARMS. 